Rotary compressor



' June 29, 1965 H. K QQQEGER 3,191,853

' ROTARY COMPRESSOR Original Filed Sept.- 27, 1961 3 Sheets-Sheet 1 HENRY H. KROEGER INV EN TOR.

June 29, 1965 KROEGER 3,191,853

ROTARY COMPRESSOR I Original Filed Sept. 27, 1961 v 3 Sheets-Sheet 2' HENRY H. KROEQER INVENTOR.

United States Patent 3,191,853 ROTARY COMPRESSOR Henry H. Kroeger, Montciair, N.J., assignor to Worthington Corporation, Harrison, N.J., a corporation of Delaware Continuation of application Ser. No. 141,058, Sept. 27, 1961. This application Nov. 16, 1964, Ser. No. 412,883 17 Claims. (Cl. 230152) This application is a continuation of my application for a Rotary Compressor, Serial No. 141,058, filed September 2.7, 1961.

This invention relates to rotary compressors of the type comprising a casing having a generally cylindrical-like bore containing a vaned rotor which divides the bore into compression means which diminish in volume from the intake to the discharge means of the casing.

It will be evident from the description which follows that the rotary compressor contemplated herein will be most effectively applied as a circulating component of a refrigeration system.

It has been customary, in constructing prior type refrigeration systems, to employ compressors of the reciprocating type. Such compressors have undesirable operating characteristics; for example, the amount of space occupied by the compressor is excessive, the cost of manufacture when compared to rotary type machines is high, and the noises created by the valves forming a part of the reciprocating compressor are unavoidable. Of still more importance is the fact that speeds of reciprocating machines are limited by the available materials for use in valve fabrication.

Until recently rotary compressor application in refrigeration systems was limited due to the critical wear area in such units.

One of the limiting factors in the operating life of a rotary compressor was caused by the development of localized wear points on the internal casing contour regulating the in and out movement of the vanes.

Attempts to overcome the foregoing problem were objectionable in that it was difiicult to pass maximum quantities of fluid to the pumping chamber of such machines in order to obtain the required volumetric efficiency.

As a consequence a higher power input was required making application of such units in refrigeration systems commercially undesirable.

To overcome the above objections applicant describes hereinafter a rotary compressor including, among other features, an internal casing contour composed of three groups of arcs arranged and disposed to provide an extremely attractive commercial unit.

Accordingly, it is an object of this invention to provide an improved high speed rotary compressor.

It is another object of the present invention to provide a rotary compressor for use in refrigeration systems including features which reduce wear on moving parts thereof, lengthen the life of rotary compressors and also provide a machine capable of delivering a high volumetric efficiency.

It is a further object of this invention to provide fluid passageways for the unit which coact to provide the required volumetric efficiency.

It is another object to provide an internal casing contour which in effect permits the entry of maximum amounts of fluid and at the same time cooperates with other features of the machine to reduce wear on the moving parts thereof.

Other objects and advantages of the invention including the basic design and the nature of the improvements Patented June 29, 1955 ice thereon will appear from the following description taken in conjunction with the following drawings, in which:

FIGURE 1 is a side elevation of a rotary compressor.

FIGURE 2is an exploded perspective view of the rotary compressor contemplated herein showing the elements thereof.

FIGURE 3 is an end view of the first stage casing.

FIGURE 4 is a section of the first stage casing taken on line 4-4 of FIGURE 3.

FIGURE 5 is a section taken through one of the inlet means of the first stage casing taken on line 55 of FIGURE 3.

FIGURE 6 is an end view of the second stage casing of the rotary compressor contemplated herein.

FIGURE 7 is a section taken through a discharge means taken on line 77 of FIGURE 6.

FIGURE 8 is a section taken through a suction means taken on line 88 of FIGURE 6.

FIGURE 9 is an end view of the partition shown as disposed between the first stage casing and second stage casing.

FIGURE 10 is an end view of the partition shown in FIGURE 9.

FIGURE 11 is an illustrative view showing development of 180 of the internal casing contour, it being understood that the remaining 180 of the internal casing contour will be developed in the same fashion.

FIGURE 12 is an illustrative View showing 180 of the developed internal casing contour and the in and out movement of the vane over this 180.

While the description and drawings of the rotary compressor contemplated herein are related to and show a two-stage machine comprising a first and second stage casing, it will be understood by those familiar with this art that the present arrangement may be used in single or multi-stage rotary units; for purposes of illustration it will be assumed that the compressor in the present illustrated form comprises two stages.

Referring to FIGURES 1 and 2 of the drawings there is shown a rotary compressor, generally designated *1 of of the hermetic type comprising a compression portion 2 and motor portion 3 respectively containing the elements of the compressor and motor.

While a hermetic unit is shown, it is not intended to limit the invention to this specific form and it will be understood by those skilled in this art that the concepts described herein could also be applied to open type units.

In operation low side fluid of a refrigeration system (not shown) is connected to inlet 4, centrally located in the end bell of the motor portion of the rotarycompressor. The fluid is then, as is customary, passed through the motor to the compression portion and from the compression portion to outlet 5 to the high side of the refrigeration system.

Now, referring to the rotary compressor in greater detail, means taking the form of a flange 6 is connected to the inboard end of the motor portion by any Well known method in the art.

'The flange 6 is provided with ports or passages 7 which communicate with the interior of the motor portion to permit flow of refrigerant fluid from the motor portion to the compression portion as will become more evident hereinafter.

The passages 7 are disposed 180 relative each other to provide equal distribution of fluid flowing through the motor portion 3.

Means taking the form of dowel pins 8 are disposed v on the flange to provide means for obtaining proper alignwhich is connected to the flange and motor portion in fluid tight relation by threaded members 11.

Extending out of the center portion of flange 6 is motor shaft 12 serving to provide the motive power for the compressor and which receives the vaned rotors of the compression portion 2 as will be described in detail hereinafter.

Now, referring particularly to the compression portion 2, a first casing 20 is shown and includes plural pumping chambers 21 and 22. Chamber 21 is provided with inlet and outlet means 24 and 23. Inlet and outlet means 25 and 26 are also provided for chamber 22.

It has been found that provision of plural pumping chambers and disposition of the inlets thereof so that they are spaced 180 relative each other and further disposing the discharge means of the first casing 180 relative each other permits the elimination of excessive radial forces which may be created on startup or during operation of the compressor.

The first casing 20 is mounted on the flange 6 and the inlets thereof are aligned with passages 7 to permit straight entry of fluid from the low side of the system into the pumping chambers 21 and 22.

Varied rotor 40 provided with the usual sliding vanes 41 which delineate individual pumping chambers as is well known in the art with the internal casing contour of first casing 20 is mounted in overhung relation on shaft 12.

It will be evident that an operative compressor can be fashioned by connecting end plate 60 to the first casing 20. Naturally, the usual sealing members will be provided to insure the desired fluid tight relationship between the above components.

Dowel means 27 are also formed on the first casing to provide for alignment between the end plate 60 and the first casing to insure that the outlet members 61 and 62 are properly seated in communication with the outlets 23 and 26 of the first stage.

While the end plate 60 as shown is adapted for use with a compressor including first and second casings it would be within the realm of one skilled in this art to fashion changes for the plate to adapt it for use in a compressor as described above including solely a first casing To fashion a rotary compressor capable of higher performance, applicant adds a second casing 30 similar in most respects to the first casing 20 described above.-

Thus the second casing comprises plural pumping chambers 31 and 32. Chamber 31 provided with inlet and outlet means 33 and 34 and chamber 32 provided with inlet and outlet means 35 and 36.

A plate or partition member 50 serves to separate the first casing 20 from the second casing 30, the casings 20 and 30 are mounted on opposite sides of the plate 50. Passage means 51 and 52 connect the outlets of the first casing 20 with the inlets of the second casing 30. Dowel means 8, 27, 37 and 57 connected to the above elements insure straight through flow from the low side of the refrigeration system to the high side thereof by providing for proper alignment between the above elements of the compressor during assembly.

End plate 60 is mounted to the second casing 30, and all of the above elements are connected together by bolt members such as 63 which maintains the desired fluid tight relationship therebetween to provide an operative unit.

The inlets and outlets of the first and second casings are all preferably provided with an entrance and exit configuration which provides for eflicient entry and egress of fluid being acted on by the compressor.

For example, rounded edges 28 are provided for the slotted ports 29 of the inlet members.

Plural discharge ports 38 communicate the discharge means 34 and 36 with the pumping chamber 32 and act to provide for eificient egress of the compressed fluid.

It was mentioned hereinabove that high speed performance and the advantages stemming therefrom were limited in prior type rotary compressors due to the sealing problems presented.

In this regard applicant makes provision for a novel lubricating flow pasage system generally designated 70 which permits the distribution of oil or the like through an L-shaped passage 71 in flange 6, through passage 72 in first casing 20, passage 73 in second casing 30 which are interconnected by passage 74 in plate 50. Such an arrangement provides the desired sealing, cooling and the lubricating effect to the rotating parts of the compressor.

If desirable a pressurizing means (not shown) for delivering the lubricating fluid through the above passage system may be connected to the L-shaped passage 71. In this fashion fluid is passed through the passage means with suflicient pressure to force lubricant into the first casing 20 through needle ports 75, and continue the flow of lubricant through passage 74 in plate 50 to passage 73 in the second casing 30 and into the pumping chambers of this casing through needle ports 76 communicating therewith.

It will be evident from the foregoing that it is desirable to incorporate a lubricant separator system with the discharge side of the unit so that lubricant free refrigerant can be delivered to the high side of the refrigeration system. Any well known means such as a vortex separator or lubricant trap can be associated with the compressor to provide this function.

While the inclusion of a lubrication system to seal, as above described, does in effect enhance the efliciency of the unit, :it is pointed out that another problem occurs in compressors having plural stages in one casing.

Specifically, such units have the inlet of the stage in proximate relation with the outlet of the other stage in the casing and as a consequence blowby occurs and a dropoif in efliciency results due to the leakage. In order to ovecome this blowby or leakage and to provide optimum operation applicant contemplates constructing the internal casing contour of the compressor with means that preclude same and permit operation at higher efliciency. In the portion of the description which follows while arcs are referred to it is evident that the curve passing through the point of maximum vane stroke may be elliptical in form, which permits variation of the volume on the suction side. Accordingly, while arcs are used in describing this curve it is not intended that this portion of the casing be limited to this form.

Referring to FIGURES 11 and 12, the internal casing contour generally designated 80 comprises are 81 having a dimension between 10 and 20 and which is concentric with the vaned rotor and of slightly greater dimension than the rotor, additional arc designated 82 connected to the ends of the above mentioned arc and which subtends an angle between 12 and 30 measured about the rotor center. The additional arc is eccentrically disposed relative the rotor. An are designated 83 is connected to the end of the additional arc to complete of the contour of the internal casing configuration.

In describing the construction of the internal casing contour development of 90 will be treated in detail and since the remaining 270 is constructed in identical fashion it is believed unnecessary to continue with the detail of the construction of this remaining portion as such construction will be clear to one skilled in the art from the description which follows.

The additional arc is provided with a configuration which will provide the desired vane tip loading required for the operation that the machine will be confronted with.

For example, in selecting this configuration lubricating properties, materials used and like considerations are analyzed. In this fashion you can plot a point 84 on a line a predetermined angle from the are 81.

Now, having established this point, applicant proceeds to lay out are or curve 83 which passes tangentially through point 84 and through a point 85 on the vertical centerline of the rotor corresponding to the maximum vane stroke of the compressor. This is accomplished by selecting a center 87 which provides a radius that permits passing arc 83 tangentially through point 84 and through point 85. This center will be on a point lying on the vertical centerline of the rotor where the bisector of the line connecting points 84 and 85 passes.

It is now possible to lay out are 82 for it is contemplated that said are be tangent to both point 84 and point 86. With these conditions the center of are 82 must lie at a point 88 where a line passing through point 86 and center of rotor intersects a line passing through point 8.4 and point 87. g

It will be evident from the foregoing that a calculation of radius R and to provide a desired configuration to arc 82 will also locate center 87 of are 83.

It is now possible to first construct arc 81 as mentioned above, strike arc 82 having a radius R and angle 0 lying on line R and finally strike are 83 having a radius R From the foregoing it will be evident that the internal casing configuration comprises portions of arcs and each quadrant thereof including an arc concentric with the rotor which controls leakage between stages; an are having its center on the vertical centerline of the rotor and said arc passing through a point on this vertical centerline corresponding to maximum vane stroke of the particular unit, which are exists over a predetermined angular extent and passes through a predetermined point lying on the end of the additional arc; and an additional are between both of the above arcs and tangent to both of said arcs.

In this fashion the internal casing contour for the 90 of cam surface is completed, and as was pointed out hereinabove the remaining 270 of cam surface is completed in identical fashion.

FIGURE 12 shows an illustrative view of the developed contour and in and out vane movement for 180, it being pointed out that the first arcs are concentric with the rotor and the remaining arcs being eccentrically disposed relative the rotor to provide a high speed rotary compressor capable of efiicient operation in a refrigeration installation.

Although this invention has been described with reference to specific apparatus, it will be appreciated that a wide variety of changes may be made within the ability of one skilled in the art without departing from the scope of this invention. For example, some of the components of the apparatus may be reversed, certain features of the invention may be used independently of others and equivalents may be substituted for the apparatus and method steps, all within the spirit and scope of the invention as defined in the appended claims.

What is claimed is: i

1. The internal casing contour for a rotary compressor including a vaned rotor, said internal casing contour comprising two arcs between and 20 concentric with the vaned rotor and said arcs having a radius of greater dimension than the vaned rotor, a second set of arcs connected to each of the opposite ends of the last mentioned arcs and being between 12 and 30 and said second set of arcs eccentrically disposed relative the vaned rotor, said second set :of arcs having a radius passing thru a point lying on the rotor centerline and said point being spaced from the center of said rotor, and connecting arcs for joining said second set of arcs to complete the internal casing contour.

2. The internal casing contour claimed in claim 1 wherein the two arcs are each 15.

3. The internal casing contour claimed in claim 1 wherein the second set of arcs are each 21.

4. The internal casing contour claimed in claim 1 wherein the connecting arcs are eccentrically disposed relative the vaned rotor.

5. A rotary compressor comprising a casing including plural pumping chambers, inlet and outlet means connected to each of the pumping chambers, a vaned rotor disposed within said plural pumping chambers to act on fluid passed to said plural pumping chambers, and said casing having an internal contour configuration comprising two arcs between 10 and 20 concentric with the vaned rotor and said arcs having a radius of greater dimension than the vaned rotor, a second set of arcs connected to each of the opposite ends of the last mentioned arcs and between 12 and 30 and said second set of arcs eccentrically disposed relative the vanedrotor, said second set of arcs having a radius passing thru a point lying on the rotor centerline and said point being spaced from the center of said rotor, and connecting arcs for joining said second set of arcs to complete the internal casing contour.

6. The rotary compressor claimed in claim 5 wherein the two arcs are 15 and the second set of arcs are 21.

7. The rotary compressor claimed in claim 5 wherein the connecting arcs are eccentrically disposed relative the vaned rotor.

8. The rotary compressor claimed in claim 7 wherein the radius of the two arcs equals the radius of the vaned rotor plus .001 times the radius of the vaned rotor.

9. A rotary compressor comprising, a casing including plural pumping chambers, inlet and outlet means connected to each of the pumping chambers, a vaned rotor having :a predetermined maximum vane stroke disposed Within said plural pumping chambers to act on fluid passed to said plural pumping chambers, and said casing having an internal contour configuration comprising two arcs between 10 and 20 concentric with the vaned rotor and said arcs having a radius of greater dimension than the vaned rotor, two arcs having their centers on a vertical centerline of the vaned rotor and passing through a point on the vertical centerline corresponding to the maximum vane stroke and each of said arcs extending over a predetermined angular extent and passing through a point lying a predetermined angular extent from said first mentioned arcs and arcs connecting each of the above arcs and being tangent to each of the above arcs and said last mentioned arcs covering an angularv extent that provides a predetermined load on the tips of the'vanes of said rotor.

10. A rotary compressor comprising a first and second casing and a partition, said first andsecond casings connected to opposite sides of said partition, each of said casings including plural pumping chambers and each of said casings having an internal contour of like configuration, inlet and outlet means connected to the plural pumping chamber of said first casing, inlet and outlet means connected to the plural pumping chamber of said second casing, a vaned rotor disposed in each of said first and second casings, means in the partition connecting the outlets in the first casing to the inlets of the second casings, inlet means connected to the inlet means of the first casing for supplying working fluid thereto, means connected to the outlets of the second casing for receiving fluid discharged therefrom, the internal contour of said first and second casings comprising two arcs between 10 and 20 concentric with the vaned rotor and said arcs having a radius of greater dimension than the vaned rotor, a second set of arcs connected to each of the opposite ends of the last mentioned arcs and being between 12 and 30 and said second set of arcs eccentrically disposed relative the vaned rotor, said second set of arcs having a radius passing through a point lying on the vaned rotor center line and said point being spaced from the center of said vaned rotor, and connecting arcs for joining said second set of :arcs to complete the internal casing contour.

11. The rotary compressor claimed in claim 10 wherein the two arcs are 15 and the second set of arcs are 21.

12. The rotary compressor claimed in claim 10 wherein the connecting arcs are eccentrically disposed relative the vaned rotor.

13. The rotary compressor claimed in claim 10 wherein the radius of the two arcs equals the radius of the vaned rotor plus .001 times the radius of the vaned rotor.

14. The rotary compressor claimed in claim 10 wherein the outlet means of the first casing are in axial alignment with the inlet means of the second casing.

15. The rotary compressor claimed in claim 10 including passage means in the first and second casings, means in the partition interconnecting said passage means, and lubricating means connected to the passage means for supplying lubricating fiuid to said rotary compressor.

16. A rotary compressor of the hermetic type compris ing a first and second casing and a partition, said first and second casings connected to opposite sides of said partition, each of said casings including plural pumping chambers and each of said casings having an internal contour of like configuration, inlet and outlet means connected to the plural pumping chambers of said first casing, inlet and outlet means connected to the plural pumping chambers of said first casing, inlet and outlet means connected to the plural pumping chambers of said second casing, a motor means connected to said first casing and including a shaft extending into said first casing and saidshaft passing through said partition and extending into said second casing, said motor means, first casing, partition and second casing being in fluid tight sealing relation, a first vaned rotor mounted on said shaft and disposed in said first casing, a second vaned rotor mounted on said shaft and disposed in said second casing, the outlets of said first casing being in axial alignment with the inlets of said second casing, means connected to the inlets of the first casing and passing through said motor means for supplying working fluid to the plural pumping chambers of said first casing, a discharge chamber having an outlet and connected to the outlet means of the second casing for receiving fluid discharged therefrom, said internal contour of said first and second casings comprising two arcs between 10 and 20 concentric with the vaned rotor and said arcs having a radius of greater dimension than the vaned rotor, a second set of arcs connected to each of the opposite ends of the last mentioned arcs and being between 12 and 30 and said second set of arcs eccentrically disposed relative the vaned rotor, said second set of arcs having a radius passing through a point lying on the vaned rotor center line and said point being spaced from the center of said vaned rotor, and connecting arcs for joining said second set of arcs to complete the internal casing contour.

17. A rotary compressor of the hermetic type comprising a first and second casing and a partition, said first and second casings connected to opposite sides of said partition, passage means within the first and second casings, means in the partition connecting said passage means, lubricating means connected to the passage means for supplying lubricating fluid to said rotary compressor, each of said casings including plural pumping chambers, inlet and outlet means connected to the plural pumping chambers of said first casing, inlet and outlet means connected to the plural pumping chambers of said second casing, a motor means connected to said first casing and including a shaft extending into said first casing and said shaft passing through said partition and extending into said second casing, said motor means, first casing partition and second casing being in fluid tight sealed relation, a first vaned rotor mounted on said shaft and disposed in said first casing, a second vaned rotor mounted on said shaft and disposed in said second casing, the outlets of said first casing being in axial alignment with the inlets of said second casing, means connected to the inlets of the first casing and passing through said motor means for supplying working fluid to the plural pumping chambers of said first casing, and a discharge chamber having an outlet and connected to the outlet means of the second casing for receiving fluid discharged therefrom.

References Cited by the Examiner UNITED STATES PATENTS 1,443,764 1/23 Smith 230-158 1,531,607 3/25 Green 230158 1,894,943 1/33 Dennedy 230207 2,016,315 10/35 Calzoni 103-136 2,274,519 2/42 Barrett 29-1564 2,467,121 4/49 Ferris 29-1564 2,538,193 1/51 Ferris 103-136 2,551,623 5/51 More 230-139 72,628,568 2/53 Rhine 230-158 2,791,185 5/57 Bohnhoff 103-136 2,824,687 2/58 Osterkamp 230-158 2,831,631 4/58 Peterson 230152 2,833,465 5/58 Cable 230-152 2,877,946 3/ 59 Garrison et al. 230207 2,894,677 7/59 Nash 230207 2,902,935 9/59 Dinnison et a1. 230-158 2,961,151 11/60 Fobian 230-152 3,040,973 6/62 Wessling 230-158 3,082,937 3/63 Tucker 230139 KARL J. ALBRECHT, Primary Examiner. 

